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Patented Sept. 27, I898. W. G. PRESTON. ELEVATOR SAFETY ATTACHMENT.

' (Application filed Apr, 22, 1897.) N 0 M o d e l zHHHHHHL!!!HHEEHE!!! WITNESSES V INVENTOH William C Pmsah A Tram/Em WILLIAM o. PRESTON, or PROVIDENCE, RHODE ISLAND, ASSIGNOR To JOHN 13.. TAFT, or EDGEWOOD, RHODE IsLANn,

ELEVATOR SAFETY ATTACHMENT.

SPECIFICATION forming part of Letters Patent No. 611,332, dated September 27, 1898. Application filed April 22, 1897. Serial No. 633,298. (No model) To aZZ-whom it may concern.-

Be it known that I, WILLIAM G. PRESTON, of Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Elevator Safety Attachments; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to the class of devices designed for elevators for the purpose of securing greater safety in operating them. It is fully explained and illustrated in this specification and the accompanying draw- Ings.

Figure l is a perspective view of an elevator-car with the safety device attached to it and a part of the elevator-shaft with one of the doors. Fig. 2 is an enlarged representation of the safety-attachment, showing its application to the starting rope or cord. Fig. 3 is an enlarged view of that part of the safety device that is connected with the shaft-door.

The object of this invention is to make it impossible to start the elevator-car either up or down while the shaftdoor is open and also to make it impossible to open the shaftdoor when the car is not opposite to it. This is accomplished inthe following manner:

Referring to Fig. 2, an enlarged view of a double eccentric is seen that is placed on the top of the elevator-car B. A is a vertical plate attached to the top of the car just back of the starting-cord a. C O are four eccentrio-shaped plates held to swing freely on four studs 6 e, that are made fast in the plate A. These eccentrics are arranged in pairs, the

"cams of each pair facing each other,with the starting-cord a between them, and the lower pair of eccentrics are placed in a reversed position to the upperpair. The eccentrics of each pair are connected to each other by spiral springs s s, fastened to each eccentric by screw-studs in the cams. These springs s draw the cams of each pair together, so as to clamp the cord a when they are not drawn back by the electromagnets m m placed back of them. There is one magnet for each eccentric, and the inciting-wires 0f the magnets are connected into the circuit of the electriccircuit wires w 10, which are connected with some source of electricity. (Not shown.)

In Fig. 3 are shown the devices and their arrangement for preventing the door of the shaft from being opened when the elevatorcar is not on a level with it. This consists of an eccentric 0, held free to swing on a stud h, fast in the framework S of the shaft over the shaft-door d. This eccentric c is placed so that when it is held up by an electromagnet n placedover it its lower corner will be clear of the top of the door (1 and the door will be free to open. This magnet n is at tached to the frame of the shaft, and its i11- citing-wire is included in the electric circuit of the wires to w; but between the magnetwire and one of the wires w a circuit-breaker is included, attached to the frame of shaft in the path of the car B, so as to be operated by it when the car comes opposite to it. This current-breaker consists of a sliding contactpin 19, held in a socket, and is thrown out by a spring, so as to be struck by a block b on the car when the car comes opposite to it, and a plate r, which is placed so as to be in contact with the pin 19 when the the block b on the car pushes it in. The plate r is connected by a wire 2' to the one end of the wire of the magnet n, the other end of the wirebei'ng connected to wire w,and the pin 19 is connected with the wire w by the wire 25, so that when the car R is opposite the door at the block b will push the pin pagainst the plate 7', and the circuit through the wire of magnet 02 will be closed and that magnet will draw up the eccentric cand allow the door 61 to be opened; butwhen the car leaves the door the pin. 10 will spring out and breakthe circuit through the wires t and i, and the magnet n will let the eccentric a drop on the door and prevent it from being opened. The circuit that incites the magnets m m on the car has a current-breaker at the side 'of the door d similar to the one just described and so placed on the frame S that the sliding pin j will be pushed back when the door is closed against the plate f and close the circuit through the wires to w by the wires connected withthe pin 25, the plate f, which will pass electric current through the wires of the magnets 'm m, so that they will draw back the eccentrics O clear of the cord at and allow the car to be started; but when the door d is opened the connection is broken at the pin j and plate f, the magnets will cease to hold back the eccentrics O C, and the springs s s will clamp them on the cord a, so that the car cannot be started.

From the foregoing it will be readily seen that when the car R is not at a landing the door 01 cannot be opened because the circuit is broken at the pin 19 and plate r, which allows the eccentrics C to clamp the cord at, and that when the door 61 is open the car R cannot be started by the cord at because the circuit is broken at the pin j and plate f, which allows the eccentric c to fall on the top of the door.

Having thus described my improvements, I claim as my invention and desire to secure by Letters Patent 1. In an elevator safety attachment, the combination of eccentrics pivoted to the car and adapted to clamp and hold the startingcord, springs for bringing said eccentrics into their clamping positions, electromagnets which when energized draw said clamps out of their clamping positions, an electric circuit in which are included said electromagnets, and circuit-breakers in said circuits adapted to be operated by the opening of an elevator-shaft door so as to break said circuit and denergize said magnets, substantially as described.

2. In an elevator safety attachment the combination of four eccentrics arranged to clamp and hold the starting-cord it pulled in either direction, springs to close each pair of clamps, an electric magnet held back of each eccentric to draw it from the cord when said magnets are energized, with wires to conduct an electric current to said magnets, substantially as described.

3. In an elevator safety attachment the combination of four eccentrics arranged to clamp and hold the starting-cord in either direction, springs to close each pair of clamps, an electromagnet held back of each eccentric to draw it from the cord when said magnets are energized, with wires to conduct an electric current to said magnets, a circuit-breaker arranged to open or close said current by the opening, and closing of the shaft-door, substantially as described.

4:. In an elevator safety attachment the combination of an eccentric arranged over the shaft-door to prevent the door from being opened, an electric magnet placed over said eccentric to draw it from contact with the door when said magnet is energized and wires I to conduct an electric current to said magnet,

a circuit-breaker arranged to close and open said current by the elevator coming to the door and leaving it,substantially as described. In testimony whereof I have hereunto set my hand this 20th day of April, A. D. 1897.

WILLIAM C. PRESTON. In presence of- H. E. BARLOW, BENJ. ARNOLD. 

